An approach on ecosystem services classification and valuation.

The study of ecosystem services and their valuation is a hot-pot issue in ecology,which plays an important role in boosting sustainable ecosystem management.At present,there are no systemic theories in ecosystem services classification and valuation,and most domestic studies are focused on the repeated estimation of some prevalent services by using established methods,without any pertinence and exploration.Based on our previous studies and related literatures,this paper put forward a new classification system of ecosystem services,and named three new concepts,i.e.,top-drawer ecosystem services,theoretical value,and actual value.A case study on the Sangyang wetland of Wenzhou further illustrated these classification system and new concepts.It is suggested that if the main purpose of ecosystem services study is to serve decision-making,it is no need to evaluate all the ecosystem services of a region accurately and roundly,while the valuation of several top-drawer ecosystem services is sufficient.The comparison of theoretical and actual values could help to analyze the degree of ecosystem degeneration and evaluate the process of ecological restoration.